Sadly, whenever a friend of mine tells me she has no butt, it makes me laugh.  I think of Hank Hill on King of the Hill and then don’t laugh out loud, because she would not be particularly happy with me about that.  But at the same point in time, some people do have no butt at all, and when she wears the wrong pants, she definitely looks like it.  But the reality is that if you have that problem, some people have a genetic tendency to store fat in one place rather than another, it just happens that way. 

Now if you want to slim down in general or in certain places, the best thing to do is to participate in general cardio.  However, if you want to tone the butt you can do exercises.  It won’t reduce or expand the fat in the butt area specifically.  But it can tone muscles, which can add definition and sometimes a bit of bulk.  You can first of all squat.  This is the best known way to tone butt and thighs.  You can also do a back lunge.  This is particularly effective, more effective keep in mind than the front lunge in terms of that kind of effect.  Finally, you can try the doggy raise.  All of these things should be done with caution should you have back problems, knee problems, or otherwise.  But they will help.